The pop cans are a great idea. This trombe wall project is still not quite finished, and some black metal in there is definitely going to be used. I need to do the hot water tank trick, but where my tank is located makes it a bit awkward. I have cabinets and stuff in the garage and don't want to relocate them. But it's on the list. Hot water will now cost me as much as heating the house in winter. The other project on hold for now is photovoltaic grid tie. A solar district is in the works at the county govt. When it goes active in the next year or two I'll be able to finance a few kw of pv on the roof without going to a bank. It will just be a property tax increase instead and the intrerest will be at about the prime rate, not prime plus 8%. Hopefully I'll be able to get the house about 80% solar, Heat, AC, etc. Only the way the roof faces will prevent 100% solar. Mabye I'll put some pv on racks in the backyard though, it just depends on the deal from the solar district, and how rates go in the future. If we hit the break even numbers using the district financing, I'll go big on the pv. Right now, using bank financing, PV is still a bit more expensive than grid power.
On the south side of the house, last years project, more of a heat collector than a trombe wall used black painted corrugated roofing for the heat exchanger. A few 2x4's permanently screwed to the wall have two of the glass panels, with the black painted steel underneath. Behind that, two holes in the wall vent the air by convection. Closing the vents in the night keep it from becoming a convection cooler. On the south side, actually facing south-southeast, I have a big tree that shades that wall in the morning in the summer till about noon when the overhang shade hits the glass. But in winter, the sun rises in a different place, and I get heat from sunup till about 3:00 pm. So on that side, I don't need to worry about a black wall in the summer since it gets shaded. On that side of the house, there is also a 4' x8' window collecting heat and you guessed it, my winter curtains are black painted metal. I could let the sun hit the floor and heat it, but the metal causes convective air circulation to spread the heat to the room better. Also on that side, I glassed in the front porch. It doesn't produce all that much heat, but that part of the exterior wall never gets below freezing, and so the kitchen wall is always warmer and I lose little heat through that wall.
On the new project, facing west- soutwest, I also have some trees coming along to shade that wall in the summer, but they are just starting to get big enough. Till they do, I'll just remove the glass seasonally. This time it's a true trombe wall, so I will be putting a lot of buckets of water in there behind the metal. Most of the heat will be brought into the house to warm it in the afternoons when the south east side is shutting down for the day. But the water will make enough warm thermal mass to keep the trombe wall way above freezing on even the coldest nights, for here, about 15F. That way, all night that wall of the house will never be cold, and any heat lost through the wall gets trapped, at least for awhile, in the trombe wall space.
The long term plan is to take the same glass, and build collectors for a roof install. But that costs a bit more, and needs ducting, thermostatic fans, atmospheric dampers to close it when the fan shuts off, etc. So for at least this year the trombe wall is cheaper.
Of course, my heat bill is a joke to most of you in a climate where most winter days see 50F for a high, and many 60F. But this house has no gas line, and electric heat bills were a shock the first few years. Used to gas heat in the previous house, costing mabye $70 a month, the first winters bills in the new house were about $180 a month.
The next few winters we heated mostly with the fireplace, burning several cords of wood, along with the work that goes with that. Finally we wised up and put more insulation in the attic. At that point, $100-125 a month heated the house, even after a 30% rate increase on the power. Last year, with the solar collectors and the porch glassed in, the bill dropped to $50-75 a month. I'm hoping to heat my house this january for less than $30, while having it 70F inside rather than 65. I still use the fireplace, but only on stormy days, and burn about a half a cord a year. The rest of the time that damper is shut as tight as possible.
The other project on the list is up insulating the walls. This one is a bear, remove sheetrock, furr out the wall thicker, insulate and re install sheetrock. We may never get the whole house done, but would like to do at least the bedrooms. Possibly this spring. I also need to put a roof on the house, we got hail last summer. That part of owning this house will definitely suck.
The big hole in my house is the dog door. A kid could drive a trike through it. Part of the new wall, where the window is, has a second dog door under the window. So now cold air, flies etc have to make it through two dog doors. At night, I close a door to seal off the dog doors but in daytime the dogs have the door open in all weather.